Welcome to the forum. The Hub 2 is just your router, to watch NOW TV you will need a compatible device, but it doesn't have to be a NOW TV box.
Have a look at the following list of supported devices as you might find you already have something that you can watch entertainment on. If not, a NOW TV box or NOW TV Smart Stick is probably your cheapest option.
If you do have another compatible device such as a games console, Roku, Chromecast etc that you want to set up, you can find more details here
@Sarahbelle You do get the option to buy a NOW TV box with broadband but it costs extra, you don't get one free anymore. Are you interested in watching the NOW TV passes or would you rather not bother?
Ifyou don't have any supported devices such as games consoles, Roku, Chromecast, Apple TV then you can pick up a NOW TV Smart Stick for £15 (£20 with 2 months entertainment or 1 month cinema) to watch on (also gives you other apps such as BBC iPlayer/ITv/4/5/UKTV, Sky Store, YouTube etc).
If you're not interested though you should be able to get a refund for your passes if you explain you've bought in error and don't have a supported device.
Yeah I appreciate if you're new to NOW TV they have that many passes and products it's gets confusing. The content's quite a bit different to Netflix, with NOW TV you get live channels as well as boxsets and catch-up, it's like having a cut down version of Sky TV.
Have a look at the following help pages which tells you more about what's on
and you can also have a look at what boxsets and movies you get here
Then if you decide you'd rather not have them I'd suggest giving NOW TV a call, explain you bought by accident and you don't have anything to watch it on and ask if they can cancel and refund you.